Exercise: I suggest you walk. If you will be spending the majority of your time consumed in your programming addiction and taking care of your new child, the best exercise for you is walking. Walking will drastically reduce the chance of you getting an injury, which could stop you from doing any form of exercise. Also, more intense forms of cardio or weights require a good amount of sleep to be effective. Walking is also something you can do with your baby. If you currently aren't doing any form of exercising now, start with a 20 minute walk the first week. Over a month or two try to increase the walk to an hour.
Flexibility: If you decide to do more intense cardio (or even if you don't), I suggest you work on flexibility. There are some great books on stretching, and there is also yoga :) Flexibility will help prevent injury (especially as your baby turns into a toddler). Yoga also consists of breathing exercises, which have been reported by many as beneficial to their overall health.
Sleep: I suggest you do your best to keep it consistent. This means going to bed at the same time and always sleeping a minimum number of hours. Eight hours is recommended, but some research has shown the older you are, the less sleep you need. I would avoid the 20 minute naps in your condition, as the REM sleep you would get from a solid 5+ hours of sleep would be very beneficial. I have not had a child yet, but I believe it will be difficult, so good luck! If you are sensitive to caffeine, do your best to avoid it a few hours before sleeping. Also, pay attention to the last meals or foods you eat before sleeping. Some may help you sleep better, and others may ruin a potential good night sleep.
Diet: Use the general BMI scale and your a low exercise level to determine how many calories you should eat in a day. I would suggest a low fat (less than 20%), and a low protein (less than 25%) diet. Stick with a variety of vegetables, fruits, whole grains, and if you are not a vegetarian, fish, lean meats, and low fat dairy products. If you are not getting 4-5 different colors of foods every day from vegies/fruit, and/or if you are not eating any meats, I would suggest looking into supplements (but that's a whole different long conversation). If you have a hard time keeping within the recommended calories, try to slowly increase more fiber into your diet. Both fiber and protein have shown effects of curbing hunger. Do you best to avoid bleach/enriched flour, processed sugar, and salt. Drink plenty of water (8+ cups a day).
Congratulations on the baby, and good luck!